/Engine/Source/Runtime/Landscape/Classes/LandscapeComponent.h
Deletes a layer from this component, but doesn't do anything else (assumes the user knows what he's doing, use DeleteLayer otherwise)
void DeleteLayerAllocation ( const [FGuid](API\Runtime\Core\Misc\FGuid) & InEditLayerGuid, int32 InLayerAllocationIdx, bool bInShouldDirtyPackage )